Recently, a greenhouse effect due to CO2 is pointed out as a cause of global heating, and countermeasures for this have rapidly become imperative across the world for preserving the earth environment. Every human activity field in which fossil fuel burns generates CO2 and demand for CO2 emission control becomes greater. With this, a method for removing and recovering CO2 in flue gas by bringing the flue gas of a boiler into contact with an amine CO2 absorbent and a method for storing recovered CO2 without releasing it to atmosphere are intensively studied for power generating facilities such as a thermal power plant in which a large amount of fossil fuel is used.
As a step of removing/recovering CO2 from the flue gas by using such CO2 absorbent, a step of bringing the flue gas into contact with the CO2 absorbent in an absorber and a step of heating the absorbent which absorbs CO2 in a regenerator to liberate CO2 and, regenerating the absorbent and circulating the regenerated absorbent in the absorber again to reuse are adopted (for example, refer to Patent Literature 1).
Also, in addition to a case in which CO2 in the flue gas is recovered, for example, in a case in which H2S in carbon gasification gas is recovered by a gasification gas purifying system, a method for absorbing H2S in the carbon gasification gas in the absorber and regenerating the absorbent in the regenerator to circulate and reuse is adopted (for example, refer to Patent Literature 2).